I got hit in the left topmost part of the head severely by an iron gate, a month ago. i took pain-killers, yet the pain didn't go. help!

A significant blow: To the scalp causing a force down the long axis of your body is a potentially significant injury not only to the skull and underlying brain, but to the axial skeleton particularly the neck. I hope you had appropriate exam and if indicated, imaging studies. Don't just rely on analgesics. If that kind of pain persists go back to your doctor.